Herein, a base‐controlled protocol was developed for the C−N coupling of primary amines and 2‐chlorobenzimidazoles, affording a handful of secondary or tertiary amines in a selective fashion. Moreover, this protocol was realized under transition‐metal‐free conditions, and the variation of the base from iPr2NH to LiOtBu completely switched the selectivity from monoarylation to diarylation. Further investigations elucidated that the variety, intrinsic basicity and amount of the utilized bases considerably affected these reactions.

Herein, a metal-free and solvent-free protocol was developed for the C–N coupling of heteroaryl halides and amines, which afforded numerous heteroaryl amines or their hydrochlorides without any external base. Further investigations elucidated that the basicity of amines and specific interactions derived from the X-ray crystallography analysis of 3j′·HCl played pivotal roles in the reactions. Moreover, this protocol was scalable to gram scales and applicable to drug molecules, which demonstrated its practical value for further applications.

In this work, a Cs2CO3‐promoted synthetic approach was identified for (hetero)aryl ether synthesis via the C−O coupling of various (hetero)aryl chlorides and alcohols/phenol. To our delight, the reactions could be carried out under transition‐metal‐free and solvent‐free conditions. Moreover, analytical‐grade reagents and air atmosphere were readily tolerated. To showcase the practical usefulness of the present protocol, the assembly of a bioactive molecule was facilely realized and the gram‐scale production of selected ether products was also efficiently accomplished. In addition, density functional theory (DFT) studies, along with a few mechanistic experiments, were conducted to elucidate a proposed reaction pathway and rationalize the pivotal role of Cs2CO3 in promoting this process. Hopefully, this work could provide useful information for researchers who are engaging in C−O cross‐coupling reactions.

Herein, we designed and presented a novel benzimidazole-based fluorescent molecule P1 via the construction of Cl bridges. Notably, the structure of P1 was authenticated by X-ray crystallography. Besides, the photophysical properties (absorption and fluorescence spectra) of this molecule were investigated. Furthermore, the fluorescence emission of P1 was further rationalized by density functional theory (DFT) calculations, which illustrated the influence of bridging Cl atoms on the energy level and energy gap (Eg).